Tennessee Titans running back Chris Johnson's domain is getting invaded. He's letting it be known he doesn't like it. With the signing of former New York Jets running back Shonn Greene earlier this month, the Titans have added a back to complement Johnson in the backfield. But the three-year, $10 million contract the Titans gave Greene leaves Johnson feeling threatened and concerned. "I have never been a big fan of the two-back system, so I don't know how we plan on using him," said Johnson via The Tennessean, reiterating comments he made to NFL.com last month. "I'm not afraid of competition, but I was thinking we'd maybe get a draft pick for the other back. And you don't give a guy that kind of money to be just a goal-line guy and in tough-yardage situations. So we'll see what happens."